mc68ec060 Freescale Semiconductor, Inc, mc68ec060 Datasheet - Page 339

• Manufacturer Part Number: mc68ec060
• Description: Mc68060 Superscalar 68k Microprocessor Including The Lc060 And Ec060
• Manufacturer: Freescale Semiconductor, Inc

11.4 THERMAL MANAGEMENT
The maximum case temperature (Tc) in C can be obtained from the following equation:
where:
In general, the ambient temperature (T
The thermal resistance from case to outside ambient (
parameter once a buffer output configuration has been determined. Reducing the case to
ambient thermal resistance increases the maximum operating ambient temperature. There-
fore, by utilizing methods such as heat sinks and ambient air cooling to minimize
higher ambient operating temperature and/or a lower junction temperature can be achieved.
However, an easier approach to thermal evaluation uses the following equations:
where:
The total thermal resistance for a package (
and
tion to the package case surface (
cannot influence it,
heat sink and airflow, can significantly reduce
junction temperature or a higher ambient operating temperature. The following tables can
be used to aid in deciding how much of air flow and heat sink for proper thermal manage-
ment.
Data for the “no heat sink” cases are derived from MC68040 PGA package characteristics.
The MC68060 PGA package has similar thermal characteristics as the MC68060 PGA
Package. The heat sink used for the “with heat sink” cases are based on the Thermalloy
2333B heat sink. Since exact power dissipation figures for the MC68060 are unavailable at
the time of printing, linear interpolation of these tables can be used to provide rough esti-
mates. Table 11-1, Table 11-2, and Table 11-3 list the thermal data.
MOTOROLA
ca
T
T
T
P
T
T
T
. These components represent the barrier to heat flow from the semiconductor junc-
jc
ja
c
c
j
a
a
j
d
= T
= T
= T
= T
= Thermal Resistance from the Junction to the Ambient (
= Maximum Case Temperature
= Maximum Junction Temperature
= Maximum Power Dissipation of the Device
= Thermal Resistance between the Junction of the Die and the Case
a
j
j
j
– P
– P
– P
+ P
d
d
d
d
ca
jc
jc
ja
ja
is user dependent. Good thermal management by the user, such as
– P
or
d
ca
M68060 USER’S MANUAL
jc
) and
a
) in C is a function of the following equation:
ca
ja
. Although
) is a combination of its two components,
ca
achieving either a lower semiconductor
jc
ca
is package related and the user
) is the only user-dependent
jc
Applications Information
+
ca
)
11-17
ca
, a
jc